Case IH F51 – Transmission Controller / Processor: Temperature Sender Open Circuit

The transmission controller has detected an open circuit in the transmission oil temperature sender or its wiring harness. When this code is active, the system defaults to assuming the transmission oil is hot. If the oil is actually cold, the operator will experience sluggish shifting and a higher-than-normal clutch pedal position during inching.

• MXM
• Case IH MXM Series
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Case IH MX Series
• MX80C
• MX90C
• MX100
• MX110
• MX120
• MX135
• MX150
• MX170
• Case IH Magnum Series
• Case IH Maxxum Series
• Case IH Puma Series

1. 1

   Disconnect the transmission processor connectors (C100 & C101)

2. 2

   Disconnect pin C100-18. Test the wiring for an open or short circuit from the terminal of the sender to the chassis

3. 3

   With the temperature sender installed, check for a short to earth/ground

4. 4

   If the wiring harness checks out OK (no opens or shorts), test the temperature sender unit (C023) itself for internal continuity/resistance

5. 5

   Use diagnostic Menu Mode H9, Channel 2 to monitor the live temperature readings the controller is seeing

1. 1

   Locate sender

   Locate the transmission oil temperature sender on the transmission housing.

2. 2

   Inspect wiring

   Inspect the sensor's pigtail and the main wiring harness for chafing, broken wires, or corroded connector pins.

3. 3

   Repair wiring

   Perform the continuity checks outlined above. If a broken wire is found between the sender and the transmission controller (pin C100-18), repair the wiring harness.

4. 4

   Remove faulty sender

   If the wiring is intact but the sensor fails the resistance test (reads completely open), unthread the faulty temperature sender from the transmission housing. (Note: Have a catch pan ready as a small amount of transmission fluid may leak).

5. 5

   Install new sender

   Install the new transmission temperature sender and reconnect the wiring harness.

6. 6

   Clear code

   Clear the F51 error code from the transmission controller.

7. 7

   Perform calibration

   If shift quality has deteriorated, perform a transmission/EDC calibration setup procedure (often accessed via the H-Menu in calibration mode) to ensure the controller relearns the clutch fill times with the correct temperature data.